Surface interactions between Escherichia coli and hemocytes of the Mediterranean mussel Mytilus galloprovincialis lam. leading to efficient bacterial clearance

The role of type 1 fimbriae in the interactions between Escherichia coli and Mytilus galloprovincialis Lam. hemocytes was evaluated. The association of fimbriated strain MG155 with hemocyte monolayers at 18 degrees C was 1.5- and 3- to 4-fold greater than the association of unfimbriated mutant AAEC072 in artificial seawater and in hemolymph serum, respectively. Such differences were apparently due to different adhesive properties since MG155 adhered more efficiently than AAEC072 when hemocytes were incubated at 4 degrees C to inhibit the internalization process. Hemolymph serum increased both association and adherence of MG155 two- to threefold but did not affect association and adherence of AAEC072. MG155 was also 1.5- to 1.7-fold more sensitive to killing by hemocytes than AAEC072, as evaluated by the number of culturable bacteria after 60 and 120 min of incubation. The role of type 1 fimbriae in MG155 interactions with hemocytes was confirmed by the inhibitory effect of D-mannose. In in vivo experiments MG155 cells were cleared from circulating hemolymph more rapidly than AAEC072 cells were cleared. These results confirm that surface properties are crucial in influencing bacterial persistence and survival within mussel hemolymph.     

Diagnosis of natural killer cell lymphoma by cytology and flow cytometric immunophenotyping. A case report

BACKGROUND: Natural killer (NK) cell lymphoma is a rare type of non-Hodgkin's lymphoma. It classically presents in the nasal region in Asian patients. There are few reports of its cytologic features. We describe a case that we diagnosed by fine needle aspiration (FNA) biopsy using flow cytometry immunophenotyping and cytomorphology. CASE: A 55-year-old, Chinese man presented with symptoms consistent with nasal obstruction. At examination, a polypoid lesion extending from the nose to the back of the throat was found. An intraoral FNA biopsy was performed. Representative smears were obtained and the remainder of the material sent for flow cytometry. A diagnosis of NK cell lymphoma was made. The patient was given chemotherapy and radiotherapy, with complete resolution of the lesion. Recurrence was noted on follow up seven months later. Pieces of tissue were taken for histology and flow cytometry and showed recurrent NK cell lymphoma. The lesion was again successfully treated by chemotherapy followed by radiotherapy. CONCLUSION: In the correct setting, a definitive diagnosis of non-Hodgkin's lymphoma can be made by FNA biopsy. This case of NK cell lymphoma was diagnosed by FNA biopsy using cytomorphology, flow cytometry immunophenotyping and clinical correlation.     

Mixed-lineage kinase control of JNK and p38 MAPK pathways

Mixed-lineage kinases (MLKs) are serine/threonine protein kinases that regulate signalling by the c-Jun amino-terminal kinase (JNK) and p38 mitogen-activated-protein kinase (MAPK) pathways. MLKs are represented in the genomes of both Caenorhabditis elegans and Drosophila melanogaster. The Drosophila MLK Slipper regulates JNK to control dorsal closure during embryonic morphogenesis. In mammalian cells, MLKs are implicated in the control of apoptosis and are potential drug targets for many neurodegenerative diseases.     

Helicobacter pylori virulence genes and host IL-1RN and IL-1beta genes interplay in favouring the development of peptic ulcer and intestinal metaplasia

Helicobacter pylori infection outcome might depend on genotypic polymorphisms of both the bacterium and the host. We ascertained: (1) the functionality of H. pylori oipA gene; (2) the polymorphism of the hostinterleukin (IL-1beta) gene (-31 C/T) and of the IL-1RN gene (intron 2 VNTR); (3) the association between the above genes and the histological and pathological outcome of H. pylori infection. One hundred and sixty-five H. pylori positive and 137 H. pylori negative subjects (23 gastric adenocarcinoma, 58 peptic ulcer, 221 gastritis) were studied. oipA was sequenced, IL-1beta was RFLP analysed. Antral and body mucosal biopsies were histologically evaluated. Functional oipA genes were correlated with cagA gene; both genes were significantly associated with gastritis activity, peptic ulcer and gastric adenocarcinoma. In these patients heterozygousIL-1RN 1/2 and IL-1beta C/T genotypes were more frequent than in gastritis patients. Intestinal metaplasia was associated with cagA, functional oipA and IL-1RN 2 allele. In conclusion, peptic ulcer and the preneoplastic intestinal metaplasia are associated with H. pylori virulence genes and with IL-1RN 2 host allele. An interplay between bacterial virulence factors and cytokines genotypes, is probably the main route causing H. pylori infection to lead to benign mild disease, benign severe disease or preneoplastic lesions.     

Targeting Tat and IFN(alpha) as a therapeutic AIDS vaccine

Evolution to AIDS is characterized by a progressive cellular immune suppression. Although there is substantial evidence for several mechanisms involved in disrupting the immune response by induction of apoptosis in responder cells by contact with infected cells, we propose that humoral factors also play a role, and that one such factor is the extracellular form of the human immunodeficiency virus (HIV)-1 Tat protein and another is IFN(alpha). Both Tat and interferon-alpha (IFN(alpha)) inhibit antigen-stimulate T-cell proliferation, and specific anti-Tat and/or anti-IFN(alpha) Abs prevent generation of HIV-1-induced suppressor cells. We propose that high titer anti-Tat and/or anti-IFN(alpha) Abs, neutralizing extracellular Tat, and/or IFN(alpha), induced by vaccines described here, antagonize HIV-1-induced immunosuppression. Innocuous vaccines were prepared by using inactivated but immunogenic Tat (Toxoid) and inactivated and immunogenic IFN(alpha) (kinoid) derivatives. Both Tat Toxoid and IFN(alpha) kinoid were well tolerated and elicited specific neutralizing antibodies (Abs) in mice, monkeys, and seronegative and HIV-1-infected individuals.     

Taste aversion learning and aging: a comparison with the effect of dorsal hippocampal lesions in rats

The relationship between hippocampal function and aging was explored in Wistar rats using taste aversion learning by comparing the performance of adult dorsal hippocampal lesioned and fifteen-month-old intact rats with that of adult intact rats. In experiment 1 the conditioned blocking phenomenon was absent in the hippocampal and the aging rats. Unlike the adult intact rats, the hippocampal and aging rats were not impaired in acquiring a learned aversion to a cider vinegar solution (3 %) presented as a serial compound with a previously conditioned saccharin solution (0.1 %). In experiment 2 both the hippocampal and the aging rats developed reduced aversions to a saline solution (0.5 %) followed by an i.p. injection of lithium chloride (0.15 M; 2 % b.w.) if the taste solution was previously preexposed without consequences. This latent inhibition effect was similar to that seen in intact adult rats. In both experiments, the aging rats exhibited enhanced conventional learned taste aversions. It is concluded that aging is not a unitary process but induces both hippocampal dependent and hippocampal independent complex changes in the functioning of the neural circuits, implementing taste aversion learning.     

A journey with T cells, primate/human retroviruses and other persisting human T-cell tropic viruses

A study of the growth of primate/human T cells led to mechanisms for temporary laboratory culture of these cells (discovery of interleukin-2) and also their continuous culture (by immortalization after infection with human T-cell lymphotropic virus type 1 or 2 (HTLV-1 or 2)). Cultures of lymphocytes also led us to isolate five persisting T-tropic viruses: 1. the Hall's Island strain of gibbon ape leukemia virus, 2. HTLV-1, 3. HTLV-2, 4. human immunodeficiency virus and 5. human herpes virus-6 (HHV-6). This report is a brief synopsis of the discoveries of the first human retroviruses, the HTLV.     

Active versus passive anti-cytokine antibody therapy against cytokine-associated chronic diseases

Current therapeutic vaccine trials in major chronic diseases including AIDS, cancer, allergy and autoimmunity, target antigenic pathogens but not the pathogenic stromal cytokines which can be major sources of histopathologic processes. Considering that the limited efficacy of these vaccines has been ascribed to local pathogen-induced cytokine dysfunction, we propose to antagonize pathogenic cytokine(s) by high affinity neutralizing auto-Abs triggered by specific anti-cytokine vaccines. As anticipated by theoretical considerations, animal experiments and initial clinical trials showed that anti-cytokine immunization was safe, well tolerated and triggered transient high titers Abs neutralizing pathogenic cytokines but, in contrast to conventional vaccines, no relevant cellular response was observed. Advantages of active versus passive anti-cytokine Ab therapy, particularly for long-term treatments, as those required in AIDS, cancer, allergy and autoimmunity include greater ease of maintaining high Ab titers, lack of anti-antibody responses and low cost.     

Role for mannose-sensitive hemagglutinin in promoting interactions between Vibrio cholerae El Tor and mussel hemolymph

The role of mannose-sensitive hemagglutinin (MSHA) in Vibrio cholerae O1 El Tor interactions with hemolymph of the mussel Mytilus galloprovincialis was studied. Bacterial adherence to and association with hemocytes were evaluated at 4 and 18 degrees C, respectively. In hemolymph serum, the wild-type strain N16961 adhered to and associated with hemocytes about twofold more efficiently than its mutant lacking MSHA. In artificial seawater (ASW), no significant differences between the two strains were observed. N16961 was also more sensitive to hemocyte bactericidal activity than its MSHA mutant; in fact, the percentages of killed bacteria after 120 min of incubation were 60 and 34%, respectively. The addition of D-mannose abolished the serum-mediated increase in adherence, association, and sensitivity to killing of the wild-type strain without affecting the interactions of the mutant. A similar increase in N16961 adherence to hemocytes was observed when serum was adsorbed with MSHA-deficient bacteria. In contrast, serum adsorbed with either wild-type V. cholerae El Tor or wild-type Escherichia coli carrying type 1 fimbriae was no longer able to increase adherence of N16961 to hemocytes. The results indicate that hemolymph-soluble factors are involved in interactions between hemocytes and mannose-sensitive adhesins.